The invention relates to a process for locating mobile stations in a cellular mobile radio network.
Various processes have been disclosed for charging usage fees (tolls) for roads and highways. Until now, though, the only method used widely has been tollbooths where cars stop and after payment of the toll, are permitted to drive the toll road. This leads to traffic jams on heavily travelled roads, despite a multitude of individual payment stations. Even devices where the driver slows down and throws a coin into a basket bring only limited relief.
Furthermore, processes have been disclosed for automatically ascertaining and debiting usage fees. In the process described in NTZ, Vol. 46 (1993), No. 4"Zukunftige automatische Gebuhrenerfassung fur den StraBenverkehr" Future Automatic Toll Recording for Road Traffic!, toll charging points are equipped with devices in which a communication takes place between the charging point and the vehicle.
In systems of this kind, position determination, namely determining whether a car is passing a toll charging point or is on a toll road, is of considerable significance. Beacon systems using infrared or microwaves have been disclosed for position determination. A radio transmission is used exclusively for position determination. In systems of this kind, often considerable structural measures are required.
A detection system described in VDI-Nachrichten VDI Reports! dated Aug. 20, 1997, pages 2 to 3 uses a position determination of the vehicle with the aid of the GPS system (global positioning system), with which a position determination is carried out using satellites. Apart from the GPS system possibly not being precise enough for the purposes of charging tolls, a position determination with the aid of the GPS system requires an additional expenditure in vehicles.